Installation of new hardware onboard a platform to perform a specific task is often a greater expense than an operator may desire. For example, integration costs of rewiring an aircraft to install an upgraded Global Navigation Satellite System (GNSS) positioning system are, in many cases, prohibitive. An existing GNSS receiver may be 1) sufficient in terms of its performance, 2) fully integrated with the onboard systems such that integrators have little motivation to upgrade the receiver.
Positioning system Anti-Jam (AJ) performance may be one characteristic the operator may prefer to upgrade. However, existing systems inherit limitations from the associated infrastructure. For example, traditional platforms may have an existing federated positioning system receiver and navigation function in which the operator has heavily invested. The cost of system integration and qualification for a new integrated GNSS system are seen as prohibitive or impossible to justify (e.g. re-wiring an aircraft for new functionality). Moreover, an existing federated interface may be bandwidth limited and unable to support transferring the desired signals or information from the AJ system to the positioning system.
To improve AJ performance, traditional applications tend to employ an analog or digital nuller located at the antenna to provide a protected Radio Frequency (RF) signal to the existing positioning system receiver in the aircraft using the existing coaxial cable that was previously connected to a Fixed Radiation Pattern Antenna (FRPA).
In some traditional systems, a digital interface AJ and GPS is used where the multi-beam output from the AJ system located near the antenna is fed serially through the existing coax. However, this approach also 1) has bandwidth limitations that restrict the number of digital beams that maybe be provided to the GPS receiver and 2) may implement a proprietary interface between the AJ and GPS that may require them to be installed in pairs. The bandwidth limitation is exacerbated when Military Signal (M-Code) receivers begin operation as each beam now requires additional bandwidth.
Modernized GNSS upgrades to existing infrastructure may be an additional goal for the operator. Modernized GNSS capabilities (e.g., M-Code) to existing system infrastructure may be desirable for certain operators. Integrating AJ with modernized GNSS has additional barriers beyond those associated with integrations. As discussed above, federated AJ solutions with a digital beam interface for modernized GNSS will require more bandwidth, exacerbating limitations associated with the current AJ to GNSS receiver interface. In addition, modernized GNSS will require specialized integration of modernized anti-spoofing with GNSS AJ. This integration challenge may act to deter operators from equipping platforms with AJ solutions in the near term.
Similar to the above example of AJ capabilities, there are several significant characteristics of existing GNSS receivers which may require enhancement to remain a viable GNSS receiver. New GNSS constellations are becoming available which emit signals that some existing GNSS installed receivers are unable to process. Military operators may desire to operate GNSS receivers with only civilian GNSS signal reception capabilities due to their exemplary user interface characteristics. In addition, military operators may procure a civilian or civilian-based vehicle previously configured with an installed and fully integrated civilian GNSS receiver. There is increasing concern that civilian and military receivers may be subject to attack by spoofing systems which corrupt or emulate one of more of the existing receivers expected positioning signals, which may corrupt the positioning capabilities of the existing receiver.
Consequently, a need exists for an effective system and method for transferring enhanced capabilities of a surrogate receiver to a host receiver via existing host infrastructure without alteration to the existing host infrastructure.